How to Replace a Kohler Toilet Gasket

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Kohler toilets are known for their quality and style. They come in all shapes, sizes and colors to complement your bathroom decor. But even these toilets can develop leaks over time. One of the most common toilet leaks is a broken gasket. Symptoms of this are a sewer odor in the bathroom and the presence of water around the base of the toilet. Before you pay for an expensive plumber, try these steps to replace your Kohler toilet gasket yourself.

Items you will need

  • Kohler toilet gasket

  • Wrench

  • Screwdriver

  • Alcohol/cleaner

  • Old rags/towels

  • Caulk or silicone sealant

Turn off the water supply to the toilet tank. Check beneath the toilet tank where you should see a hose running into the wall. This is the water supply line. On this line there should be a valve. Turn this valve off.

Flush the toilet. This will allow the water to run out of the tank. To get all the water out, take the cover off the top of the tank. There should be a chain connected to a rubber flange at the bottom of the tank. Pull on this chain and let all the water in the tank run out.

Use the wrench to disconnect the water supply hose.

Lay old rags or towels on the ground beneath the toilet. Unscrew the two bolts that hold the tank to the base of the toilet. This is tricky because the head of the bolt is inside the bottom of the tank, while the nut that keeps the bolt in place is at the bottom of the outside of the tank. With smaller Kohler models, use a screwdriver to hold the bolt steady while you undo the nut with a wrench. On larger models, find a friend to help you.

Lift the tank off the toilet and carefully set it upside down on your towels or rags on the floor.

Take off the bolt protectors at the base of the toilet. These cover the bolts on either side that secure the toilet to the flange. When you remove these, you will see the nuts and washers that hold the toilet in place. Unscrew these.

Gently rock the toilet from side to side. What you want to do is break any silicone or caulk seals that hold the toilet in place.

Turn the toilet bowl over gently and set it down on the rags. Clean off the remnants of the old toilet gasket on the bottom of the toilet. Stuff a bunch of rags down the flange hole to prevent sewer gases from seeping up.

Gently press the new wax toilet gasket into place around the drain opening. Run a line of caulk or silicone sealer around the bottom of the toilet where it touches the floor.

Insert new bolts (if any) into the flange mounted in the floor.

Turn the toilet bowl over and lower it back over the flange. This part is tricky because you need to ensure that the toilet drain and wax ring are over the flange, while, at the same time, make sure the flange bolts fit through the holes in the bottom of the toilet bowl.

Install the new gasket on the bottom of the tank.

Turn the tank over and gently place it back on top of the toilet bowl, making sure the bolt holes are aligned. Insert the bolt and washer assembly through the holes in the bottom of the top of the tank.

Thread the nuts and rubber washers back onto the bottom of the bolts projecting through the bottom of the tank and through the toilet bowl. Tighten these nuts at first by hand, then with the wrench. As you tighten with the wrench, do one side at a time so that you make a tight seal.

Reconnect the water supply to the tank and turn it back on. Wait for the tank to fill with water and then flush. Check for leaks.


  • Don't overtighten the bolts. This could crack the porcelain.


  • Make sure you have plenty of towels or rags on hand. Even when you think you've got all the water out of the toilet, more will appear. Open the windows and make sure the area you are working in is well-ventilated.